Today it is still Christmas. It was not even Advent when you spotted your first Christmas tree; John the Baptist had scarcely begun to preach repentance when you sent your first card. You ate your first mince-pie and sang your first carol long before Mary and Joseph reached Bethlehem. Yet now, when the parties and presents have faded to a memory, when we have struggled back to school and work, Christmas is still with us. On the first day of Christmas my true love sent to me . . .

Why should Christmas last so long? The Church offers us 12 whole days to celebrate, to assimilate, to reflect. Twelve whole days to unfold the mystery of the single word Emmanuel, "God with us". But isn't the time in fact absurdly short? Twelve days in which to comprehend the presence of the living God! "And the light shineth in the darkness, and the darkness apprehended it not . . . He came into his own, and they that were his own received him not" (John I.v,11). His own people failed to grasp the astonishing fact that the Word of God had come to dwell among them. Yet we expect to tuck it away in our minds within the span of a Midnight Mass.

The familiar traditions of Christmas are double-edged; for by their familiarity they allow us to domesticate the Word of God. We all know what Christmas is really about. We want to escape the world of commerce and competition, and recover untarnished those stories we have known from infancy: the Virgin with child, the babe in a manger, the shepherds, the colourful kings from the East. The Word was made flesh and dwelt among us; and each year we settle briefly, nostalgically, upon St John's comforting claim. But have we made it too comfortable?

For the Word that was made flesh was the Word of the living God. The God who cannot be contained by the galaxies, because He created them. The God whom Isaiah could not address until his lips had been cleansed with burning coals. The God who will not be locked safely away in the past, in first-century Palestine or in the memories of our childhood, because He is summoning us, challenging us, here and now. If we can strip away the nostalgia, to hear with fresh ears the words of our carols, to see with fresh eyes the illustrations on our cards, that is the message that they will give us. But it is a message so explosive that we cannot hear it all at once.

The liturgy of the Church reflects our limitations. However devotedly, however joyfully we have celebrated the explosive moment itself, we need time to gather the sparkling fragments thrown by its force across the world it has reshaped. Thus the series of feasts after Christmas: of St Stephen, the first Christian martyr; of St John the Evangelist, the most brilliant of witnesses to the incarnation; of the innocent children slaughtered by the fear of King Herod; of the motherhood of Mary, the mother of God. Every moment of the mystery calls for meditation: "And Mary kept all these sayings, pondering them in her heart" (Luke ii,19).

Finally, to the feast of Epiphany, today. Over the centuries, this ancient festival has attracted to itself many moments from the life of Christ. It recalls his baptism, when the obedient servant was revealed as the beloved Son of God. It recounts the visit of the Magi, when the Jewish child-king was first acknowledged by the gentiles. It commemorates the wedding-feast at Cana, when Jesus rescued the festivities by turning water into wine. Here again, the theme is the manifestation of Jesus as the Christ: this was the first sign of his transforming power, and a symbol too of the gloriously gratuitous generosity of God.

Each episode is a lens that refracts a single ray from the light of the incarnation. We cannot gaze directly at the mystery. We can absorb it only partially, gradually. We need the Christmas season; we need the multiplicity of its images. For only with their help can we begin to glimpse the time- worn truth with fresh eyes.

To glimpse it, but not to grasp it. To see it, but not to seize it. Rather to allow it, to allow Him, to seize us. For if Christmas belongs primarily to us, then it will pall as soon as we weary of punch and mince-pies. But what if it really is Christ's Mass, God's own feast, "a million times told lovelier, more dangerous", and inexhaustible in its meaning? If so, then Christmas is truly still present, God in his limitless glory still dwelling among us. Happy Christmas, Happy Epiphany, and a Happy New Year.

Tourists are limp, leaderless and distinctly UnAustralian

Andrew Grice: Inside Westminster

Blairites be warned, this could be the moment Labour turns into Syriza

The mystery of Britain's worst naval disaster is finally solved - 271 years later

Exclusive: David Keys reveals the research that finally explains why HMS Victory went down with the loss of 1,100 lives

'I saw people so injured you couldn't tell if they were dead or alive'

Nagasaki survivors on why Japan must not abandon its post-war pacifism

The voter Obama tried hardest to keep onside

Outgoing The Daily Show host, Jon Stewart, became the voice of Democrats who felt the President had failed to deliver on his ‘Yes We Can’ slogan. Tim Walker charts the ups and downs of their 10-year relationship on screen